Birdsong Birdsong is the classic example of how genes (hereditary information) and environment both have a crucial role to play in the behavioral development of animals. Since the pioneering work of W. H. Thorpe on chaffinches (a common European bird), many species have been studied, and it has become clear both that learning plays an important role for all species and also that there are constraints on what they are able to learn. The word “pioneering” in the passage is closest in meaning to •A.recent•B.famous•C.original•D.controversialThorpe was able to show that learning from others was involved in chaffinch birds through a series of experiments on hand-reared chicks (young birds). As in most other species, only the males sing. Thorpe found that, if he raised young males in total isolation from all others, the song they produced was quite different from that of a normal adult. It was about the right length and in the correct frequency range. It was also split up into a series of notes as it should be. But these notes lacked the detailed structure found in wild birds, nor was the song split up into distinct phrases as it usually is. This suggested that song development requires some social influence. Later experiments in which researchers played recordings of songs to young birds showed just how precise this influence was: many of them would learn the exact pattern of the recording they had heard. A remarkable feature here was that birds were able to copy precisely songs that they only heard in the first few weeks of life, yet they did not sing themselves until about eight months old. They are thus able to store a memory of the sound within their brain and then match their own output to their recollection of it when they mature. According to paragraph 2, researchers discovered which of the following by playing recordings of songs to chaffinches? •A.Chaffinches could no longer be taught to reproduce sounds after thefirst few weeks of life.•B.Chaffinches could not reproduce songs with exactly the same patternsof recorded songs.•C.Chaffinches at the age of eight months could recall and reproduce asong that they heard in the first few weeks of life.•D.Chaffinches that learned a song from recordings in the first few weeksof life were later unable to copy the sounds of mature chaffinches.All of the following are mentioned in paragraph 2 as characteristics of wild chaffinches EXCEPT: •A.They are able to copy songs very precisely.•B.Their song development requires interaction with other chaffinches.•C.Their songs are not as well-structured as the songs of other birds.•D.It is the males of the species that do the singing.Young chaffinches normally learn only chaffinch song, though Thorpe found they could be trained to sing the song of a tree pipit (another type of bird), which is very similar to that of t...
